# US 10,121,587 B2 · Manufacturing method of magnetic element

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- Number: US 10,121,587 B2
- Document ID: US10121587B2
- Status: Granted
- Kind: B2
- Application number: 15/007,666
- Filed: 2016-01-27
- Published: 2016-08-04
- Granted: 2018-11-06
- Earliest claimed: 2015-02-03
- Assignees: Sumida Corporation
- Applicants: Sumida Corporation
- Inventors: Satoru Yamada
- Web page: https://patentgrep.com/patent/US10121587B2

## CPC

- H01F 41/0246: {Manufacturing of magnetic circuits by moulding or by pressing powder (magnetic cores made by moulding or by pressing powder H01F27/255; soft magnetic particles H01F1/20, H01F1/36)}
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES

## Abstract

A manufacturing method of a magnetic element including the steps of: sandwiching and holding at least one of a terminal unit and a coil terminal-end of a coil between a tubular-shaped upper-side die and a tubular-shaped lower-side die; filling a magnetic material in the tubular-shaped portion; and pressure-molding a core, whose side surface follows the inner walls of the upper-side die and the lower-side die by using an upper-side punch and also by using a lower-side punch, wherein at least a portion of the inner wall of the upper-side die and at least a portion of the inner wall of the lower-side die have respective different distances with respect to the center of the tubular-shaped portion, and in the step of pressure-molding, there is formed a core concave-portion having a step on the outside surface of the core, by transcription, and at least one of the terminal unit and the coil terminal-end is at the boundary.

## Claims

### Claim 1

A manufacturing method of a magnetic element, comprising the steps of:
sandwiching and holding at least one of a terminal unit and a coil terminal-end of a coil between a tubular-shaped upper-side die and a tubular-shaped lower-side die, while the coil is positioned in a tubular-shaped portion constituted by the upper-side die and the lower-side die;
filling a magnetic material in the tubular-shaped portion after the step of sandwiching and holding; and
pressure-molding a core, whose outside surface follows the inner walls of the upper-side die and the lower-side die, by pressurizing the magnetic material, which was filled in the step of filling, using an upper-side punch from the upper side and also by using a lower-side punch from the lower side, wherein
at least one portion of the inner wall of the upper-side die and at least one portion of the inner wall of the lower-side die are spaced by respective different distances from the center of the tubular-shaped portion and, due to the difference in said respective distances, a step is formed in the tubular-shaped portion at a position where said at least one of the terminal unit and the coil terminal-end is sandwiched, and
in the step of pressure-molding, there is formed, by transcription of the step in the tubular-shaped portion, a core concave-portion comprising a step on the outside surface of the core, with at least one of the terminal unit and the coil terminal-end as a boundary.

### Claim 2 (depends on 1)

The manufacturing method of a magnetic element according to claim 1, wherein
for the core concave-portion, there is provided a terminal concave-portion which is recessed in a surface of the core, said surface having a mounting side and a side opposite to the mounting side, the terminal concave-portion being provided between the terminal unit and said side opposite to the mounting side, and
there is further comprised a step of bending the terminal unit toward the mounting side by setting the step on the mounting side of this terminal concave-portion as a fulcrum.

### Claim 3 (depends on 1)

The manufacturing method of a magnetic element according to claim 1, wherein
the terminal unit has a root side proximal to the core and the root side is recessed from the outside in the width direction so that it has a narrower width than that of the distal side of the terminal unit.

### Claim 4 (depends on 1)

The manufacturing method of a magnetic element according to claim 1, wherein
in the step of pressure-molding, there is formed a terminal concave-portion which is recessed from the side surface of the core and concurrently into which the terminal unit enters; and in the inside of the terminal concave-portion, there is integrally formed a conductive-wire concave-portion which is recessed compared with the aforesaid terminal concave-portion.

### Claim 5 (depends on 4)

The manufacturing method of a magnetic element according to claim 4, wherein
the portion, at which the terminal unit and the terminal-end are positioned within at least one of the lower-side die and the upper-side die, is provided in a flat shape.